Offset Gains and Carry Forward Losses: How to Settle Trading Losses

TL;DR

• 손익통산 (loss offsetting) nets gains and losses within the same tax period, and 손실 이월공제 (loss carryforward) moves remaining losses to later tax periods for offsetting.
• The process is reconcile trades → collect statements and proofs → prepare and submit filings → register carryforward if applicable. Verify latest rules with your broker or tax office.

1. Difference between loss offsetting and loss carryforward

Loss offsetting nets profits and losses that occur within the same tax period, for example within one year. Loss carryforward applies when losses remain after offsetting and allows those losses to be carried into subsequent tax periods to offset future gains. Both can be used together, but eligibility and requirements differ, so check your individual situation.

2. Documents and trade reconciliation (Step 1)

1) Obtain annual trade statements: get yearly transaction records and profit and loss statements from your broker. 2) Collect proofs for dividends, fees, and other income: organize documents for dividend income and related items. 3) Verify account separation: if you have multiple accounts, aggregate profits and losses by account. Check your broker and the tax office for the latest forms and submission methods.

3. Calculation and filing preparation (Step 2)

1) Sum total gains and total losses within the tax period. 2) After applying loss offsetting, if residual losses remain, review whether they meet the criteria for carryforward. 3) Complete the filing according to comprehensive income tax filing or the appropriate separate filing category. To reduce errors, crosscheck calculations with broker-provided documents.

4. Submission methods and deadlines (Step 3)

Filings are made via the National Tax Service Hometax system or at a tax office. Deadlines and electronic filing availability can change annually, so confirm the latest guidance before filing. Registering for carryforward may require additional procedures.

5. Common mistakes and check items

• Misidentifying account consolidation can lead to omission of some transactions.
• Be careful not to double count items like dividend income with other income categories.
• Failure to meet carryforward requirements (filing timing, proofs, etc) can invalidate the benefit, so verify all submitted documents.

If needed, contact your broker customer service or a tax professional, and check the National Tax Service or your broker for the latest rates and deduction limits.

This article is for information only and is not an investment solicitation.